1. Field of Invention
This invention generally relates to a cap for fluids that will act as a check valve to let the fluid inside a container exit without difficulty, but at the same time will impede the entrance of other substances like air, water and dirt into the container.
2. Prior Art
Previously all caps were made just to open and close, leaving the fluid inside the container open to any kind of contamination. Later, inventors started to solve this problem, adding a closeable lid that the user must close to prevent any extraneous fluids or particle(s) from entering inside the container (e.g., flip-top caps). Sometimes this works well enough. However, in some cases, such as creams that can easily get oxidized with air and reduce their potency, this situation becomes critical. At the same time, some fluids used in medical applications need to stay clean and free of contaminants to be safe to use for human applications. All the plastic caps heretofore known in the market suffer from a number of disadvantages:                (a) All caps currently available in the market allow air to enter in the container. This can result in oxidation of the substance inside the container, it will get damaged or change its properties over time. An example would be an anti-age cream with certain vitamins that in contact with air will change color, thicken and oxidize, losing their anti-aging properties. Another example is a cream that helps to heal scars, but is not effective if put into contact with oxygen. These creams are usually very expensive.        (b) On a normal cap, any contaminants coming from the exterior can enter the container through the cap contaminating and damaging the formula of a medical product. This is especially critical in medical applications where bacteria or other microorganism can enter the container and grow inside. Later the patient who is taking this formula can get infected by the bacteria or other microorganism. This can happen to patients with a low immune system, who can die from an airborne disease coming from the container that has the medicine that is supposed to cure them, rather than infecting them.        (c) The cap needs to have the lid closed to prevent any contaminant from entering the container. Sometimes people do not like to close the lid, forget or do not have time to do it. For example, when dispensing a diaper rash cream, if the baby moves around all the time, there is not time to close the cream while putting a diaper on the baby after using the cream.        (d) The cap also needs to be closed to prevent any fluid inside the container from spilling        